This invention relates to an ultrasonic diagnosis apparatus for generating an ultrasonic image based on at least one of phase information and amplitude information contained in a signal that is created by scanning a cross section of a to-be-examined subject with an ultrasonic wave.
The conventional ultrasonic diagnosis apparatuses generally comprise a plurality of units corresponding to the manners of signal processing and image processing. These units are connected in the order according to the processes of the signal processing and image processing.
Interfaces of a fixed type corresponding to the order of connection of the units are each provided between a corresponding pair of adjacent units. A certain unit is arranged to process, in accordance with a predetermined timing signal, an image signal, for example, input thereto via a corresponding interface in a real-time manner, and then to output the process result to the next unit. Thus, in the conventional ultrasonic diagnosis apparatus, a series of processing is performed in a fixed order corresponding to the order of connection of the units.
FIG. 6 is a block diagram roughly illustrating the structure of the conventional ultrasonic diagnosis apparatus.
As is shown, the ultrasonic diagnosis apparatus comprises a plurality of units such as an ultrasonic probe 100, a rate pulse generating circuit 101, a transmission control circuit 102, a reception control circuit 103, a receiver 104, a digital scan converter (DSC) 105, an encoder 106, a monitor 107, a blood flow analysis unit 108 and a CPU unit 109.
When the operator has performed a predetermined operation for ultrasonic scanning, using, for example, an operation panel, the CPU unit 109 performs processing corresponding to the predetermined operation, thereby setting, in each unit, a parameter necessary for the ultrasonic scanning. In accordance with this setting, the rate pulse generating circuit 101 creates a basic signal (a rate pulse signal) for transmitting and receiving an ultrasonic wave. The transmission control circuit 102 drives the ultrasonic probe 100 to generate an ultrasonic pulse signal based on the basic signal. As a result, an ultrasonic pulse signal is transmitted from the ultrasonic probe 100 to a to-be-examined subject.
The ultrasonic probe 100 then receives a signal reflected from the subject. The reception control circuit 103 supplies the receiver 104 and the blood flow analysis unit 108 with the reflection signal received by the ultrasonic probe 100. As is shown in FIG. 7, the reception control circuit 103, which is called a "beam former", comprises pre-amplifiers 110 for amplifying a signal that indicates a received wave and is output from the ultrasonic probe 100, A/D converters (ADC) 111 for converting the amplified electric signals (analog signals) into digital signals, delay circuits 112 for delaying the digital signals from the respective ADCs 111, and an adder 113 for adding signals output from the delay circuits 112. The circuit 103 creates an ultrasonic reception signal, which is provided with predetermined directional characteristics by a received signal that has a predetermined delay corresponding to each ultrasonic oscillating element incorporated in the ultrasonic probe 100.
The receiver 104 subjects the received signal to predetermined signal processes such as quadrature detection, magnitude detection, filter processing, edge emphasis processing, etc., and outputs the process result, e.g. a B-mode image signal, to the DSC 105 provided after the receiver 104.
The blood flow analysis unit 108 performs signal processing such as MTI filtering, autocorrelation processing, etc., thereby generating a two-dimensional blood flow signal indicative of flow velocity, power, dispersion, etc. An FFT unit incorporated in the blood flow analysis unit 108 calculates a flow velocity distribution. The signal processing results of the blood flow analysis unit 108 are supplied to the DSC 105, superposed therein upon the B-mode image signal output from the receiver 104, and developed into a two-dimensional image. The two-dimensional image is converted by the encoder 106 into a video signal that can be displayed on, for example, a TV monitor, and is then displayed on the monitor 107.
The above-described conventional ultrasonic diagnosis apparatus has the following problems:
(1) A series of ultrasonic scanning, signal processing and display processing are performed in a fixed order as aforementioned, and therefore it is difficult to add a new function so as to enhance the performance of the apparatus.
(2) The unit structure is hard to change since it is limited by the interface rules. This means that to reduce the size or cost of the apparatus is difficult.
(3) The data flow between units is also hard to change, and hence it is difficult to access data from each unit in a desired manner. Data indicating a signal or an image obtained by ultrasonic scanning is dispersed and stored, while it is processed, in storage devices that are incorporated in the units. To access desired data from a unit for special processing other than usual image display processing, it is necessary to provide an exclusive signal line used for reading data from, for example, the CPU, as well as a signal line for usual image display. Also from the viewpoint of cost reduction of the apparatus, it is not preferable to disperse signals or images into storage devices of the units.
(4) When, for example, a failure has occurred in a particular unit, the function of the unit (for example, the blood flow display function of the blood flow analysis unit) cannot be provided unless the unit is exchanged for a new one.